Safety apparatus for elevators



y 8, 1953 E. A. SAHLIN 2,646,858

SAFETY APPARATUS FOR ELEVATORS Filed March 26, 1952 i 2 Sheets-Sheet l nag-*5 FIG 2 T sac 4455:? #4 w INVENTOR.

(BY flaw-4&4, ATTORNEY y 28, 1953 E. A. SAHLIN 2,646,858

SAFETY APPARATUS FOR ELEVATORS Filed March 26, 1952 I 2 Sheets-Sheet 2 BY fi cw ATTORNEY Patented July 28, 1953 SAFETY APPARATUS FOR ELEVATORS Eric Albert Sahlin; Harrington Park, N. J., as-

signor to Otis Elevator Company, New York, N. Y., a corporation of New Jersey Application March 26, 1952, Serial No. 278,675

The invention relates to safety apparatus for elevators, especially for elevators on airplane carners.

The invention will be described as applied to a deck-edge airplane carrier elevator. tomary with such elevators to raise and lower the elevator platform by means of separate sets of hoisting ropes, one for each end of the platform. Safety mechanism is provided for Stopping the platform in case of parting of the ropes, as where one or both sets of hoisting ropes are shot away. With the long platforms which are used, there is a certain amount of bending of the platform. Also where only one set of ropes parts, tilting of the platform takes place. These are factors which must be taken into consideration in operation of the safety mechanism.

The object of the invention is to provide for each set of hoisting ropes an elevator safety device which is of simple construction, positive in operation and in which the full application of the safety is assured regardless of bending or tilting of the elevator platform.

Features and advantages of the invention will be seen from the following description and appended claims.

In the drawings:

Figure 1 is a schematic representation in side elevation, as viewed from the exterior of the ship, of a deck-edge elevator embodying the invention;

Figure 2 is a schematic end view of'the same;

Figure 3 is a fragmental plan view, illustrating for one end of the elevator platform, the arrangement of safety mechanism of Figures 1 and '2;

Figure 4 is an end view of the same; and

Figure 5 is a detail of the safety operating mechanism.

Referring first to Figures 1 and 2, ID represents the platform of a deck-edge elevator operating outboard of the 'ships hull between the main deck II and flight deck I? of an airplane carrier. Two sets of hoisting cables I3 and I4, illustrated as single ropes, are provided, one for each end of the platform, being secured thereto by cable hitches 15. Cables I3 pass over idlers l6 and H, thence downwardly around idler 2]] to the hoisting engine 2 I, inboard of the ship. Similarly, cables I4 pass over idlers 22, 23 and 24 to the hoisting engine. All this is known construction and will not be described in detail.

Referring also to Figures 3, 4 and ,5, the elevator is vertically guided-at the ends of the platform. lhe arrangement at each end is the same. It comprises a pair of guide standards and 3! supported bythe ships hull. These standards It is cus- 6 Claims. (01. 187-75) are spaced sidewise and provided with oppositely disposed guide plates 32 and 33. A pair of rollers 34, of which but one is indicated, is provided at the top and bottom of the platform to guide the platform sidevvise and to take care of cantilever thrust. Each roller is supported on a shaft 35 carried by the platform. Also a roller 36 is provided at each end of the platform for endwise guidin and to take care of end thrust. This roller cooperates with guide plate 31 provided on one of the standards.

Safety mechanism is provided at each end of the platform. This mechanism is shown for only one end of the platform, the arrangement at the other end being the same. The safety mechanisrn comprises a buffer, and a safety brake for bringing the buffer into operation. It is freely suspended from structural work 40 extending from the platform. In the arrangement illustrated, the structural work comprises a pair of channels 4| to which a socket member 42 is secured. This socket member, along with a ball 43 formed on the head of the buffer plunger 44, provides a ball and socket joint. A bolt 45 extends through an aperture 46 in the socket member into the head of the buffer plunger. The safety brake is carried by the buffer cylinder 41 at the lower end thereof. It comprises a pair of pawls 50 and lit depending from cylinder 4'! and pivotally mounted on pins 52 carried by the cylinder. These pawls are adapted to engage with the teeth 53 of oppositely disposed racks 54 and 55, one on each guide standard. The pawls are biased to engage the racks by a spring 55 arranged on a spindle 51 depending from the buffer cylinder. This spring acts on a block 60, slidably mounted on the spindle and connected to the pawls by links iii. A trip 62 pivotally carried by spindle 5i acts on block (50 normally to hold the pawls out of engagement with the racks. This trip is actuated through a rod 63 to release the pawls when the hoisting cables part at that end of the platform. Actuatin mechanism for the rod has been schematically illustrated in Figure l as in the form of a lever 6 carried by the platform and actuated by spring 65. upon the parting of the ropes with which it is associated, to actuate lever 66 connected to the rod to pull the trip out from above the block.

In operation, upon the trip 62 being released, spring 56 forces pawls 58 and El outwardly into position to engage oppositely disposed teeth 53 on the racks 54 and 55. As this engagement takes place, buffer cylinder 4'! is brought to a stop. The end of the platform acting through channels 4| and the ball and socket joint then forces the plunger downwardly into the now stationary cylinder, gradually bringing the end of the platform to rest. This will be effected Within the stroke of the buffer as is well understood in the elevator art.

At the time of application of the safety, a switch is operated to cause stopping of the hoisting engine. This switch, designated 58, has been illustrated as actuated by lever 66 of Figure 1. With such arrangement, should the platform be ascending at the time the safety is applied at one end, the stopping of the hoisting engine steps the ascent of the other end of the platform, minimizing tilt of the platform.

To insure the desired engagement of the pawls with the rack teeth when tilting or bending of the platform is present, the safety mechanism at each end of the platform is separately guided. This guiding mechanism includes a slot 70 in each rack extending vertically midway the sides of the rack, and a pair of guide ribs H and 72, one on each side of the buffer cylinder for sliding in the slots. To allow for tilting and bending of the platform the aperture 46 in socket member i2 through which the suspending bolt 45 extends is considerably large. than the bolt and the distance between the head of the buffer plunger and the head of bolt 45 is made slightly greater than the thickness of socket member 42. This insures the full engagement of the pawls with the racks, regardless of operatin conditions.

A leader H3 is secured to the lower end of one of the pawls on one side thereof. This leader has a point ldwhich extends below the end of the pawl and cooperates with lugs on the teeth of the rack to force the pawls into full engaging position with the teeth, or else to guide the pawls on to the teeth immediately below. This obviates breaking off of the ends of the pawls and rack teeth and insures proper safety action.

Thus it will be seen that safety mechanism has been provided for each end of the platform which is of simple construction and positive in operation and which assures the platform being brought to a stop in a certain distance when the safety is brought into operation. By guiding the safety mechanism independently of the platform and suspending it freely from the platform, the desired operation of the safety mechanism is assured and with full braking force.

While a preferred arrangement has been illustrated, it is to be understood that other forms of safety mechanism may be employed. Also the details construction of the safety mechanism illustrated may be altered. Other arrangements for causing stopping of the other end of the platform may be employed. Also, the invention is applicable to other bodies which are adapted to be raised and lowered, especially those which are suspended at opposite ends or sides of the body.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that al1 matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

v 1. In a hoisting installation; an elongated body adapted to be raised and lowered; hoisting roping for said body at opposite ends thereof; guiding means for said body at said opposite ends thereof; safety mechanism for each of said onposite ends of said body, each safety mechanism I opposite ends of said platform for vertically guiding said platform; and safety mechanism for each. of said opposite ends of said platform, each safety mechanism comprising a vertical stationary member and means for engaging said member-to stop the descent of said platform, means at each end of the platform for supporting said safety mechanism for that end of said platform by said platform to enable it to hang therefrom without being subject to tilting or bending of the platform, and means for vertically guiding each of said safety mechanisms independently of said platform guiding means to insure the full application of said safety mechwhen operated.

3. In an elevator installation; an elevator platform; hoisting roping for said platform at opposite ends thereof; means at each of said opposite ends of said platform for vertically guid ing said platform; and safety mechanism for each of said opposite ends of said platform, each safety mechanism comprising a buffer, a safety brake carried by said buffer, a vertical stationary member adapted to be engaged by said safety brake to stop the descent of said buffer, in turn to stop the descent of said platform, mean including a swivel joint at each end of the platform for supporting said buffer for that end of said platform by said platform so as to be free from tilting or bending of the platform, and means associated with said vertical stationary member at each end of said platform for independently guiding said buffer at that end of said platform.

4. In an elevator installation; an elevator platform; hoisting roping for said platform at opposite ends thereof; means at each of said opposite ends of said platform for vertically guiding said platform; and safety mechanism for each of said opposite ends of said platform, each safety mechanism comprising a buffer freely suspended from the platform, a safety brake carried by said buifer, and a vertical stationary member adapted to "be engaged by said safety brake, means operable by parting of said hoisting roping for one end of said platform for causing for that end of said platform said safety brake to engage said vertical member to stop th descent of said buffer, in turn to stop the descent of said platform, and means associated with said vertical stationary member at each end of said platform for guiding said buffer at that end of said platform independently of said platform guiding means.

5. In an elevator installation; an elevator platform; hoisting roping for said platform at opposite ends thereof; guides for said platform at said opposite ends of the platform; and safety mechanism for each of said opposite ends of said platform comprising, a buffer carried by the platform, said buffer having a cylinder and a plunger connected to said platform to permit relative movement thereof, a pair of vertical racks, a pair of pawls pivotally carried by said buffer cylinder and adapted upon operation to engage the teeth of said racks during descent of that end of said platform to stop movement of said cylinder, thereby causing the descent of said platform to be retarded and finally stopped as the plunger moves downwardly in said cylinder, means for causing the operation of said pawls, and guiding means for said buffer and said pawls separate from said platform guides.

6. In an elevator installation; an elevator platform; hoisting roping for said platform at opposite ends thereof; guiding means for said platform at said opposite ends thereof; and safety mechanism for each of said opposite ends of said platform comprising, a buffer freely suspended by the platform, said buffer having a cylinder and a plunger connected to said platform with a swivel joint, a pair of oppositely disposed vertical racks, a pair of pawls carried by said buffer cylinder at the lower end thereof for cooperating with said racks, means for Withholding said pawls from engagement with said racks but operable by parting of said hoisting roping at that end of the platform for causing said pawls to engage the teeth of said racks to stop descent of said buffer cylinder, thereby causing the descent of said p1atform to b retarded and finally stopped as the plunger moves downwardly in said cylinder, and means for guiding said buffer separately from said platform guiding means.

ERIC ALBERT SAHLIN.

No references cited. 

